That guy makes it look easy, but he has like 40+ years experience working with hots and he knows his snakes very very well. But even if you know your snakes, you still work as securely as you can, because of crap like this;
https://www.youtube.com/watch?v=pVy_kW44bV0
Now getting a bite from a Gaboon, you have a real big problem. TBH I would rather have a Mamba bite, then one of those snakes which will rot a limb off with cytotoxins.